1. Field
The disclosure relates to a method, system, and computer program product for the indication of a destructive write via a notification from a disk drive that emulates blocks of first block size within blocks of a second block size.
2. Background
A plurality of disks may be coupled to a storage controller that controls the plurality of disks. For example, disks configured as Just a Bunch of Disks (JBOD), Redundant Array of Independent Disks (RAID), etc., may be coupled to storage controller. One or more hosts coupled to the storage controller may perform Input/Output (I/O) operations with respect to the plurality of disks by sending commands to the storage controller.
A sector is a specifically sized division of a disk. Previously, one sector of a disk was generally configured to hold 512 bytes of information. However, recently certain disks are being configured to hold 4096 bytes (i.e., 4 Kilobyte) of information by disk manufacturers.
A block is a group of sectors of a disk that an operating system can address. Count-key-data (CKD) is a disk data organization model of certain operating systems in which the disk is assumed to be comprised of a fixed number of tracks, each having a maximum data capacity. Multiple records of varying length may be written on each track of a CKD disk, and the usable capacity of each track depends on the number of records written to the track. CKD architecture derives its name from the record format, which comprises a field containing the number of bytes of data and a record address, an optional key field, and the data itself. CKD records are stored in 512 byte blocks and the operating system resident on a host may address the 512 byte blocks. Certain other disk data organization models may also be addressed by an operating system in 512 byte blocks.